Hair Hormones Reveal Refugee Stress Patterns over Two Years

Background

How can a strand of hair reveal the burden of war?

For children who have lived through war and forced displacement, stress is an unavoidable part of daily life. Understanding how their bodies respond to these extreme conditions can provide crucial insights into long-term mental and physical health risks. Hair hormone analysis is emerging as a powerful tool in refugee research, offering a retrospective glimpse into chronic stress exposure through biomarkers like cortisol, testosterone, and dehydroepiandrosterone (DHEA). Unlike saliva or blood samples, which only capture short-term fluctuations, hair samples provide a months-long record of hormone levels. This study explored hair hormone patterns in a large cohort of Syrian refugee children over two years, uncovering the biological footprint of war trauma. 

 

What were the aims of this study?

Can hair hormones help us understand the impact of war on mental health?

This study aimed to investigate how stress-related hormones in hair reflect the mental health and trauma exposure of Syrian refugee children. By examining cortisol, testosterone, and DHEA levels over two years, the researchers sought to determine whether these biomarkers could help predict psychological outcomes and inform targeted interventions. 

 

How was this study carried out?

From refugee camps to the lab: how researchers measured stress in hair

The study followed 1,594 Syrian refugee children living in informal settlements in Lebanon, with data collected at two time points, 12 months apart. Hair samples were carefully obtained from the posterior vertex of the scalp to ensure consistency. Participants’ mental health was assessed through validated psychological measures, while hormone concentrations were analysed using enzyme-linked immunosorbent assays (ELISA). The researchers accounted for potential confounders, including hair treatment, length, and environmental factors.

 

What were the key findings?

Stress leaves a mark – hair hormones reveal a striking pattern.

The study revealed several important findings: 

• Higher cortisol levels were linked to increased PTSD symptoms and recent war exposure, but levels tended to decrease over time, suggesting long-term stress adaptation or dysregulation.
• DHEA concentrations were elevated in children reporting higher anxiety and depression, reinforcing its role as a key stress biomarker.
• Testosterone levels did not show a clear relationship with psychological outcomes, indicating that further research is needed.
• Age and sex differences were significant; older children and girls exhibited higher cortisol levels when compared to younger children and boys, highlighting developmental and biological influences on stress responses. 
• Hair colour and environmental factors played a role, with black hair showing higher cortisol concentrations than brown hair, and external conditions (e.g., head lice, hygiene) potentially affecting hormone levels.

 

What are the implications of this research?

Can these findings help improve mental health support for refugee children?

This research underscores the importance of integrating biological measures into refugee mental health studies. The findings suggest: 

• Early identification of at-risk children: Hair hormone analysis could be used as a non-invasive screening tool to detect children experiencing chronic stress. 

• Tailored interventions: Understanding hormone patterns may help refine psychological and social support programs, ensuring interventions are targeted effectively. 

• Improved research methodologies: Future studies should standardise hair hormone analysis, account for cultural factors in sampling, and explore multi-method approaches, including genetic and neurological assessments. 

By capturing the hidden biological effects of trauma, this study paves the way for more effective strategies to support the mental well-being of displaced children. The evidence suggests that war leaves not only psychological but also physiological scars—ones that may be detectable in a simple strand of hair. 

 

About the study team 

Our multidisciplinary research team comprises experts in psychology, physiology, molecular biology, and psychiatry. Together, we collaborate on investigations into the many ways in which children are at risk, and resilient to, challenges and hardships experienced during childhood, with a focus on Syrian refugee children living in Lebanon. The study group included; Andrew May and Michael Pluess (University of Surrey); Demelza Smeeth (Queen Mary University of London); Fiona McEwen (Queen Mary University of London; King’s College London); Patricia Moghames (Medecins Du Monde, Lebanon); Elie Karam (Balamand University); Michael J. Rieder, Abdelbaset A. Elzagallaai and Stan van Uum (University of Western Ontario).